Mohican-class sloop

By the late 1850s, the United States Navy had begun the transition to steam-propelled warships across its fleet. However, these new vessels were generally large, had deep drafts, and were poorly suited for operations in shallow coastal waters. To address this gap, the Navy initiated the development of a new class of shallow-draft steam vessels in 1857. These ships were intended to feature "light draft, great speed, and heavy guns." The project received strong support from Southern congressmen, who were concerned about the possibility of the Royal Navy intercepting American ships during the enforcement of the Blockade of Africa against the Atlantic slave trade. In 1858, Congress authorized the construction of eight such vessels. One was built as a paddle steamer, while the remaining seven were ordered as screw sloops. Of these, three had a draft of 10 ft (3.0 m), and the other four had a draft of 13 ft (4.0 m).^[1]: 71

Three of the 13 ft (4.0 m)-draft vessels–Mohican, Iroquois, and Wyoming–shared a similar design. In February 1861, Congress authorized an expansion of the class. The design of Iroquois was replicated in Oneida and Wachusett; Tuscarora was based on Wyoming; and Kearsarge was intended as a near-copy of Mohican. Although the exact armament varied by ship and time period, each was designed to carry several large-caliber Dahlgren guns mounted on pivots, along with a broadside battery of six 32 lb (15 kg) cannons.^{[1]: 71 [2]: 128}All seven ships were nearly identical in size, differing by only a few inches. They measured approximately 199 feet (61 m) long between perpendiculars, with a beam of 33 feet (10 m) and a mean draft of 15.5 feet (4.7 m).^[1]: 78 Each vessel carried 165 long tons (185 short tons) of coal to supply two boilers, which generated 840 ihp (630 kW) and powered a single screw propeller, which produced a top speed of approximately 12 knots (22 km/h; 14 mph). Their initial displacement ranged from 1,457 long tons (1,632 short tons) to 1,488 long tons (1,667 short tons).^[2]: 128 Days after the American Civil War began, Congress ordered four more enlarged sloops based on the Mohican-class design. The resulting four ships of the Ossipee-class were larger in every aspect compared to their parents, even though they were intended to carry a similar armament.^{[1]: 94–95}